The ability to control gene expression at a specific stage of plant growth, or in a specific plant tissue is an ability frequently desired in genetic engineering. To achieve this, nucleic acid sequences are required that will initiate transcription in the desired tissue at the desired stage in the plant growing cycle. One application of this interest is the ability to modify the phenotype of seed tissue, e.g., modifying the protein composition, oil composition, nutritional value, and the like.
In order to isolate useful nucleic acid sequences, a product must be identified that is present in the desired tissue but not present in other tissue. This product may then be used to identify a nucleic acid sequence in the plant genome that contains the flanking regulatory regions. Once the regulatory regions have been identified and isolated, a construct must be engineered so that DNA sequences of interest may be conveniently placed in position to be regulated by these sequences. Finally, the construct must be integrated into a plant genome, and the effect of its presence determined, i.e., ability to initiate transcription and effect phenotype.
Relevant Literature
European Patent Application 0 255 378 (and related European Patent Application 0255 377) describe seed specific transcriptional regulation generally and describe examples of several promoters capable of initiating preferential transcription in various seed tissues.